JPS60125640A - Corrosion proof processing - Google Patents

Abstract

PURPOSE:To prevent the corrosion of metal and concrete by a method wherein thermoplastic resin is stuck, in the form of a film, on a flexible base material to form a sheet and, after a substance to be coated is heated, the sheet is wound thereon with pressure. CONSTITUTION:Thermoplastic resin is stuck, in the form of a film, on a flexible base material such as a metal plate, an aluminum sheet or a metal net to form a sheet. Next, a substance to be coated is heated to a temperature exceeding the melting point of the thermoplastic resin, and then said sheet is wound with pressure on said coated substance for corrosion proof. Polyethylene, vinyl chloride resin, polystyrene, polypropylene or the like can be used as the thermoplastic resin. In addition to metal and concrete, this corrosion proof method of plastic coating can be applied also to timber, paper, etc. to which corrosion proof processing can not be applied heretofore, by devising a method of heating, e.g. by using far-infrared irradiation or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a corrosion-proofing method, and more particularly to a corrosion-proofing method applied to metal products, concrete products, and the like.

Conventionally, steel frames have been used as foundation materials or structural materials in the largest quantities among metals, as they are inexpensive and have high mechanical strength, and are also the most commonly used for walls, etc. As is well known, there are concrete types that are inexpensive and have high mechanical strength.

However, such steel frames or concrete are chemically unstable and susceptible to corrosion. However, conventionally used steel materials and concrete materials do not take into account such chemical instability or susceptibility to corrosion, and are simply produced in large quantities for funeral purposes, are cheap, and are easy to process. Because it was used with only this point in mind, it often led to unexpected losses or unexpected disasters.

In order to prevent such corrosion of steel frames and concrete, various measures have been taken in the past. One of these is a corrosion prevention method in which the corroded surface of a steel frame material, concrete, etc. is coated with a thermoplastic resin coating having excellent corrosion resistance, and the material to be corroded is shielded from the corrosive environment. Here, as means for forming a thermoplastic resin film on the surface, lining, baking with powder paint, painting, coating with paint or rubber, etc. have been performed.

However, while linings made of rubber or thermoplastic resin have excellent corrosion resistance and chemical resistance, they are thin and can leave pinholes, or are dependent on adhesive materials and construction techniques when pasting. They have the disadvantage of being inferior in adsorption power and mechanical strength, or conversely, being too hard, which can cause cracks.

In addition, rust prevention using paint is widely used because lining does not require the same harsh conditions and is inexpensive and easy to use. It was a truly troublesome process, requiring careful consideration of many factors such as properties, coating method, coating conditions, and environment of the object to be coated.

In particular, depending on the installation environment of the object to be coated, for example, when lining or painting pipes buried underground, the lining layer or paint film may be cracked, scratched, pinholes, etc. due to disturbances that occur during lining and painting. However, even if the cracks are minute, they not only cause corrosion of the steel frame or concrete surface, but also cause the cracks in the concrete floor surface to cause floats and other problems. It was also expected that peeling would progress.

Regardless of which method is used, with conventional lining and painting, even if minute scratches are discovered on the steel frame surface or concrete floor surface, complete repair is required; Not only is it extremely difficult;
Even if only one damage was repaired, there was a high risk that the damaged area would gradually expand.

In order to correct the deficiencies of such conventional corrosion prevention methods, the present invention returns to the basics of why steel frames rust and why concrete flakes due to erosion. As a result, the present invention was completed.

In other words, when considering steel frames, there is the fact that they will not erode if the supply of oxygen is completely cut off and there is electrical insulation between them and the outside, while concrete is exposed to the outside and is susceptible to acids and salts. Based on the fact that steel frames begin to deteriorate and lose their cohesive power when exposed to the influence of Furthermore, the present invention is based on the idea that corrosion of metals and concrete can be prevented by reducing the effects of deterioration on concrete and connecting concrete that has lost its cohesive strength. It has now been completed.

Generally, naturally occurring iron takes the form of a stable mineral when combined with oxygen, sulfur, water, silicic acid, etc. Also, if oxygen is not dissolved in the liquid, due to hydrogen polarization,
In addition, due to the saturated ferrous hydroxide in the liquid,
All of them are well aware that corrosion of iron stops progressing.

Furthermore, although concrete has an extremely high compressive strength, it is weak against bending stress or tensile stress, and concrete that once cracks is particularly strong, so stress concentrates in the cracked area, causing the crack. It is also understood that this progresses and causes peeling and falling off phenomena.

The reason why these forms of corrosion are not determined from the ionization tendency or electrode potential is because the nature of the compounds that form on the surface is decisive for corrosion. In addition, since electrical corrosion generally occurs in buried pipes due to stray currents in the soil, it has been confirmed that polymer coatings with good electrical insulation properties, such as polyethylene, can provide excellent corrosion protection. Most molecular plastic coatings were processed in factories, and it was considered impossible to process them on-site.

Therefore, the present invention involves forming a sheet by attaching a thermoplastic resin to a flexible base material, heating the object to be coated to a temperature exceeding the melting point of the thermoplastic resin, and then heating the object to be coated to a temperature exceeding the melting point of the thermoplastic resin. This method is characterized by forming a thermoplastic resin film on the surface of the object by wrapping and pressing the sheet onto the object. Only the sheet needs to be formed at the factory, and the rest can be installed on site.

In short, the present invention focuses on the fact that thermoplastic resins can be easily remelted by heating or preheating the object to be coated.
By heating the object on site and storing heat energy above the melting temperature as preheating material, a sheet to which thermoplastic resin is attached is directly wrapped and crimped onto the object.
Since the thermoplastic resin can be melted by preheating the surface of the object to be coated, and C.I. can be adhered to the surface of the object to be coated while cooling, the working time can be significantly shortened and the cost efficiency is also great.

Here, as the flexible base material, for example, a metal plate, an aluminum sheet, a metal net, that is, a wire mesh, etc. can be used. Further, as the thermoplastic resin, the following can be used. For example, polyethylene, vinyl chloride resin, polystyrene, polypropylene, methacrylic resin, hard vinyl chloride resin, ABS resin, polyacetal, nylon resin, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polyphenylene sulfide, polysulfone, fluorinated resin. , olefin
Vinyl alcohol copolymer, polyoxybenzine, polyamideimide, polyamide bismaleide, polyarylate, polyethersulfone, polymethylpentene, polyetherketone, polyetherimide, ionomer resin based on ethylene-methacrylic copolymer, and even polyester resins. Sulfone resin, etc.

As additives for such thermoplastic resins, as rosins, WW rosin, rosin chrycerin ester,
There are hydrogenated rosin, hydrogenated rosin glycerin ester, aggregate rosin, etc. Polyterpene resins include α-pinene polymer, β-pinene polymer, divertene polymer, and aliphatic hydrocarbons include olefin and diolefin polymers. In addition to these, there are alicyclic hydrocarbon resins, aromatic hydrocarbon resins, phenolic resins, styrene resins, coumaron indene resins, polyamide resins, etc. Examples include paraffin wax, microcrystalline wax, castor wax, and chlorinated paraffin.

The objects to be coated include not only metals and cocrete, but also by devising heating methods such as far-infrared irradiation, it is possible to process plastic coatings on materials that could not be processed conventionally, such as wood and paper. This is a corrosion-resistant processing method that allows for

The above-mentioned flexible base material can be used by freely changing its original shape or, if a metallic net is used as the base material, its mesh, etc., depending on the object to be coated, and by melting the thermoplastic resin. A material having a thermal conductivity sufficient to uniformly perform the above is used by appropriately inverting the heat conductivity.

Examples are given below to explain the present invention in more detail.

Example 1 Graft a polymer (melt index 75. Density 0.95g/cm'
*Powder with melting point 85°C) and bombbutene (melt index 20 - density 0.91g/crn' a melting point 1)
A thermoplastic resin sheet is created by adhering and melting 40 to 200 meshes of powder mixed with powder at a temperature of 25°C (25°C) to a wire mesh (0.5 mm thick, mesh size 1 mm) using the flame spray method. . Note that known means other than the flame spray method, such as the flock spray method, fluidized dipping method, electrostatic powder method, flickering method, extrusion forming method, etc., may be used, but in this example, the flame spray method was used. .

Next, put the iron plate (5 x 30 x 120 cm) into a 200°C oven and heat it for about 10 minutes, then take it out.
This iron plate was pressed onto one side of the above thermoplastic resin sheet for about 5 seconds.

The bonded surface was completely melted and adhered, and no air bubbles or pinholes were observed. After cooling for about 5 hours at room temperature, the tensile strength was measured (ASTM 07-49-
JIS K-13301-58) result is 8K
An adhesive strength of more than g/cm' was obtained.

Example 2 A mortar board (Mortar composition was JIS R52Ql, curing period was 4 weeks, IX IOX IOcm) was heated by irradiating it with a far-infrared gas burner for 10 minutes, and then the same thermoplastic as in Example 1 was applied to the mortar board. The resin-adhered melt-bonded sheet was pressed for 5 seconds.

The crimped surface was completely adhered, and after being left at room temperature for about 5 hours, it was measured with a Riken adhesive force tester and the result was 10 kg/
Adhesive strength exceeding crrf was obtained.

Example 3 Commercially available ethylene vinyl alcohol powder coating [
Abbreviations: E, V, A, powder coatings, product names: Repazint (manufactured by Bayer AG, West Germany) and Mersen 900 (manufactured by Toyo Todatsu) 1 were used to create a thermoplastic resin adhesion melt-bonded sheet, and the same as in Example 1 was used. An iron plate was heated in the same manner as in Example 1, and a thermoplastic resin-adhered melt-bonded sheet was pressure-bonded to the preheated surface.

The result was an adhesive force of 8 kg/cm' or more, which was almost similar to the result of an adhesive force test using the same test method as in Example 1.

1 Example 4 A commercially available thermoplastic resin-adhered melt-bonded sheet, identical to that of Example 3, was created, and after heating the surface of the buried iron pipe with a gas burner until the surface temperature reached 200'C, the sheet was crimped. While doing so, I rolled it up and left it in place for 12 hours.

The coating thickness, including the thickness of the wire mesh, is 1 mm, and the high voltage is 1.
When the coating layer was energized using a pin-pole tester with a low voltage of 0,000 volts and a low voltage of 220 volts, a uniform insulation resistance value was obtained, and the effect of preventing the occurrence of local batteries was recognized. It has been demonstrated that it has particularly excellent practical value.

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Claims (1)

[Claims] 1. A sheet is formed by attaching a thermoplastic resin to a flexible base material in the form of a film, and the object to be coated is heated to a temperature exceeding the melting point of the thermoplastic resin. A corrosion-resistant processing method characterized by forming a thermoplastic resin film on the surface of the object to be coated by rolling and pressing a sheet.